Ўзбекистон республикаси ахборот технологиялари ва коммуникацияларини ривожлантириш вазирлиги муҳаммад ал-хоразмий номидаги

FEATURES OF 4G CELLULAR COMMUNICATION 
N. Jahongirov (master student, TUIT) 
M. Farmonov 
(master student TUIT)
 
4G (4-Generation) is the abbreviated name for the fourth generation of 
wireless telephony, based on TCP/IP technology for transmitting information. 4G 
supports speeds up to 1 Gbps for subscribers with low traffic speeds and up to 100 
Mbps for subscribers with high traffic speeds (for example, in transport) under 
optimal conditions. 
The development of information transmission technologies in the fourth 
generation network began in 2000 with the research of the Japanese company NTT 
DoCoMo. Later, such companies as Hewlett-Packard, Sprint, Imagine, Google, 
Intel, Comcast, Bright House, Time Warner, Ericsson and others joined it. Thus, 
two standards appeared: LTE (Long Term Evolutian) and WiMAX (IEEE 
802.16e), which, according to IMT-Advanced, became a new era in the develop-
ment of the network. LTE technology was developed by 3GPP as an evolution of 
UMTS technology related to 3G networks. 
International Telecommunication Union (ITU-R) radiocommunication sector 
defined a number of requirements for the international mobile wireless broadband 
4G standard, called the International Mobile Telecommunications Advanced (IMT-
Advanced) specifications, in particular setting the data rate requirements for 
serving subscribers:100 Mbit/s speed should be provided to highly mobile sub-
scribers (for example, trains and cars), and 1 Gbit/s speed should be provided for 
low-mobility subscribers (for example, pedestrians and fixed subscribers). 

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Since the first versions of mobile WiMAX and LTE support speeds well 
below 1 Gbps, they cannot be called IMT-Advanced technologies, although they 
are often referred to by service providers as 4G technologies. In turn, after the 
launch of LTE-Advanced networks by mobile operators, they began to be called 
4G + for marketing purposes. On 6 December 2010, ITU-R acknowledged that the 
most advanced technologies are considered “4G”, although this term is not defined. 
4G communication systems are based on packet data transmission protocols. 
IPv4 protocol is used for data transfer; IPv6 support is planned for the future. From 
a technical point of view, the main difference between the fourth generation 
networks and the third is that 4G technology is completely based on packet data 
transfer protocols, while 3G combines both packet switching and circuit switching. 
For voice transmission in 4G, VoLTE (Voice over LTE) technologies are provided. 
The main research in the creation of communication systems of the fourth 
generation is carried out in the direction of using the technology of orthogonal 
frequency multiplexing OFDM. In addition, for the maximum transmission rate, 
the technology of data transmission using N antennas and their reception by M 
antennas -MIMO is used.With this technology, transmitting and receiving antennas 
are spaced apart so as to achieve weak correlation between adjacent antennas. 
The structure of the LTE network is shown in Fig.1. The core of the EPC 
(Evolved Packet Core) network consists of a Serving Gateway (S-GW), a P-GW 
(Packet Data Network Gateway) gateway, a Mobility Management MME 
(Mobility Management Entity) protocol management structure connected to the S-
GW and eNodeB signaling interfaces. 
Fig.1. LTE network structure